1. Field of the Invention
The present disclosure relates to a fixing member, a method for manufacturing a fixing member, and an image forming apparatus.
2. Description of the Related Art
In a heat fixing device used in an electrophotographic image forming apparatus, such as a copy machine or a laser printer, in general, a pair of rotation members, such as a roller and a roller, a film and a roller, a belt and a roller, or a belt and a belt, are disposed so as to be pressed against each other. These rotation members form a pressure contact portion (fixing nip) therebetween. When a recording medium such as a paper sheet on which an unfixed toner image has been formed is fed into the pressure contact portion, the toner is fused by heat, thereby being fixed to the recording medium. The rotation member to come into contact with the unfixed toner image on the recording medium is referred to as a fixing member. A known fixing member has a multilayer structure including a substrate, an elastic layer formed of silicone rubber on the outer surface of the substrate, and a surface layer covering the elastic layer and made of fluororesin or any other material capable of easily releasing the toner.
The substrate and the elastic layer are typically bound to each other with an adherent coating liquid called primer. If the elastic layer is a cured product of an addition-curable silicone rubber composition (hereinafter simply referred to as silicone rubber elastic layer), a primer containing a silane coupling agent having an unsaturated aliphatic group is suitable (Japanese Patent Laid-Open No. 2014-142377). This is because the unsaturated aliphatic group of the silane coupling agent reacts with the hydrosilyl group of the crosslinking agent in the addition-curable silicone rubber, thus bonding the substrate and the elastic layer together simultaneously with the curing of the silicone rubber.
In order to ensure high adhesion between the substrate and the elastic layer, the coating film of such a silane coupling agent is baked generally at a high temperature of higher than 120° C. so that the silane coupling agent can react sufficiently with the hydroxyl groups at the surface of the substrate.
The present inventors disclose a technique for increasing the heat resistance of the fixing member, in which titanium oxide particles having an anatase crystal structure (hereinafter referred to as anatase titanium oxide) are added as a heat-resistant filler to the silicone rubber elastic layer (Japanese Patent Laid-Open No. 2014-041342).